CIAgent
88a1dab810
---ci--- phase: 7 milestone: v0.2 status: complete requirements: covered: [REQ-2-001, REQ-2-002, REQ-2-003, REQ-2-004, REQ-2-005, REQ-2-006, REQ-2-007, REQ-2-008, REQ-2-009, REQ-2-010, REQ-2-011, REQ-2-012] partial: [] ---/ci--- Milestone v0.2 (ai-tutor-architecture) merged to main. Escalation record (audit remediation, durable): P1 executor delegation failed twice (empty subagent results, zero files created); auto-resolved at full autonomy to inline execution with identical plan fidelity (commit 3271373, reflog-only after phase branch squash-delete).
118 lines
4.0 KiB
Python
118 lines
4.0 KiB
Python
"""Structured output defense — 4 layers (D-020).
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Layer 1: response_format={"type":"json_object"} request (auto-degrades on 400
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inside the provider).
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Layer 2: prompt-embedded schema hint ("Respond with ONLY valid JSON...").
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Layer 3: defensive parse — strip markdown fences, extract first balanced
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JSON object, pydantic model_validate.
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Layer 4: single bounded retry with the validation error fed back.
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"""
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from typing import TypeVar
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from pydantic import BaseModel, ValidationError
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from ..llm.base import LLMProvider
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from ..llm.types import Message
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T = TypeVar("T", bound=BaseModel)
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class StructuredOutputError(Exception):
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"""Raised when the model output cannot be validated after one retry."""
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def extract_json_object(text: str) -> str:
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"""Strip fences and return the first balanced {...} block from text."""
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stripped = text.strip()
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if stripped.startswith("```"):
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first_newline = stripped.find("\n")
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if first_newline != -1:
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stripped = stripped[first_newline + 1:]
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if stripped.rstrip().endswith("```"):
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stripped = stripped.rstrip()[:-3]
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stripped = stripped.strip()
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start = stripped.find("{")
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if start == -1:
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raise StructuredOutputError("no JSON object found in model output")
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depth = 0
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in_string = False
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escape = False
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for i, ch in enumerate(stripped[start:], start=start):
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if escape:
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escape = False
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continue
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if ch == "\\":
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escape = True
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continue
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if ch == '"' and not escape:
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in_string = not in_string
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continue
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if in_string:
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continue
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if ch == "{":
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depth += 1
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elif ch == "}":
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depth -= 1
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if depth == 0:
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return stripped[start:i + 1]
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raise StructuredOutputError("unbalanced JSON object in model output")
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def parse_structured(text: str, schema: type[T]) -> T:
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"""Layer 3: fence-strip + first-balanced-object + pydantic validation."""
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candidate = extract_json_object(text)
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try:
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return schema.model_validate_json(candidate)
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except ValidationError as exc:
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raise StructuredOutputError(f"schema validation failed: {exc}") from exc
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def schema_instruction(schema_hint: str) -> str:
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"""Layer 2: prompt-side schema text."""
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return (
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"Respond with ONLY a valid JSON object matching this schema — "
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"no markdown fences, no prose outside the JSON. "
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f"Schema: {schema_hint}"
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)
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async def structured_completion(
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provider: LLMProvider,
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messages: list[Message],
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*,
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model: str,
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schema: type[T],
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schema_hint: str,
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retry_feedback: str | None = None,
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) -> T:
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"""Full 4-layer pipeline. One bounded retry (layer 4), then raise."""
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# Build request: append schema instruction to the last user message (layer 2).
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request = list(messages)
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last_user = next((m for m in reversed(request) if m.role == "user"), None)
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if last_user is not None:
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request = [
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Message(role=m.role, content=(m.content + "\n\n" + schema_instruction(schema_hint)))
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if m is last_user else m
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for m in request
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]
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response_format = {"type": "json_object"}
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raw = await provider.chat(request, model=model, response_format=response_format)
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try:
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return parse_structured(raw, schema) # layers 1+2+3
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except StructuredOutputError as exc:
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# Layer 4: single bounded retry with error feedback
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retry_prompt = (
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f"Your previous response was invalid: {exc}. "
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f"Return ONLY the corrected JSON matching: {schema_hint}"
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)
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request2 = list(messages)
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request2.append(Message(role="user", content=retry_prompt))
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raw2 = await provider.chat(request2, model=model, response_format=response_format)
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try:
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return parse_structured(raw2, schema)
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except StructuredOutputError as exc2:
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raise StructuredOutputError(
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f"structured output failed after retry: {exc2}"
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) from exc2
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